The present invention relates to a workpiece carrier for a disk-shaped workpiece having a workpiece support with a cooling and/or heating device. The workpiece support is penetrated by a multiplicity of exit apertures communicating with a distribution space which is connected in turn to a gas feed line to form, with a gas supplied to the distribution space and between the workpiece and the workpiece support, a cushion-like gas layer. The gas acts as heat transmission means. The invention also includes a vacuum process space for the treatment of workpieces with such a workpiece carrier.
German patent document DE-A-36 33 386 discloses a carrier for a disk-shaped workpiece, namely a substrate, of the initially described type. For the treatment of such a workpiece in a vacuum treatment process, it is known therefrom to provide a recess in a seating block, corresponding essentially to the extent of the substrate. The recess is connected to a centrally disposed gas feed line.
A multiply-perforated disk is placed in the recess, over which the substrate to be treated is laid. The disk and the recess in the block thus bounds a distribution space for the gas so that, with gas flowing over the gas feed line, the distributing space and the exit apertures, a gas cushion is formed between the substrate and the workpiece support which acts as heat transmission means.
In this known seating the gas forming the gas cushion exits at the periphery of the substrate into the environment which is often undesirable in particular when using such a seating in a vacuum treatment process for the substrate. It is true that in some vacuum treatment processes a particular gas is supplied into the process space in defined quantities, however, in many cases it is desired to supply this process gas independently of a ubiquitous gas feed on the seating for heat transmission purposes.